In this review, we will be comparing RP-504C II and RP-400C, two Passive Center Channel speakers by Klipsch.
Let's have a brief look at the main features
of Klipsch RP-504C II and Klipsch RP-400C first before getting into our more
detailed comparison.
| Key Specs | Klipsch RP-504C II | Klipsch RP-400C |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Tractrix Horn | 1" Tractrix horn |
|---|
| Woofer | 4 x 5.25" Cerametallic cone | 2 x 4" Cerametallic cone |
|---|
| Frequency response | 50-25k Hz | 65-25k Hz |
|---|
| Sensitivity | 96 dB | 95 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | up to 150 watts | up to 75 watts |
|---|
| Weight | 16.50kg / 36.3lbs | 6.36kg / 14lbs |
|---|
| Dimensions (H x W x D) | 6-15/16" x 32-3/16" x 15-1/8"
177.0 x 818.0 x 385.0mm | 5-3/4" x 16-1/16" x 9-1/2"
147.0 x 408.0 x 242.0mm |
|---|
What size room are the Klipsch RP-504C II and Klipsch RP-400C speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
Klipsch RP-504C II |
Klipsch RP-400C |
| Near-field |
Poor |
Good |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
No way |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2,
Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: >
400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual
listening experience changes depending on floor height, room shape, surface materials, listening
position, speaker locations, etc.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
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Drivers
Both RP-504C II and RP-400C are 2-way speakers.
Klipsch RP-504C IIKlipsch RP-400C
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Klipsch RP-504C II |
Klipsch RP-400C |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
4 x 5.25-inch
|
2 x 4-inch
|
RP-504C II features a 1" titanium Tractrix Horn Tweeter and 4 x 5.25" Cerametallic cone Woofer with a Crossover frequency at 1950 Hz. On the other hand, the RP-400C features a 1" titanium Tractrix horn Tweeter and 2 x 4" Cerametallic cone Woofer.
Frequency Response
RP-504C II has a frequency range of 50-25k Hz whereas RP-400C has a frequency range of 65-25k Hz. With a minimum frequency of 50Hz, the RP-504C II can go significantly deeper on the low side and provide stronger bass compared to the RP-400C's min frequency of 65Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Center Channel class in our database.
Low Frequency
Center Channel Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
RP-504C II and RP-400C have the same Impedance of 8 ohms but where they differ is the sensitivity levels. RP-504C II sensitivity is rated at 96 dB and the RP-400C's is at 95 dB. This 1 dB difference makes the Klipsch RP-504C II a more sensitive speaker compared to Klipsch RP-400C, hence will play louder with the same amount of watts.
Sensitivity
Center Channel Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
RP-504C II can handle a max power of 150 watts RMS, whereas RP-400C has a max power handling value of 75 watts RMS, 75 watts less than the RP-504C II.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier — change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
RP-504C II features Binding post type posts and RP-400C has a Binding post type posts. None of these speakers feature bi-amping/bi-wiring.
Klipsch RP-504C II's Binding post terminals
Klipsch RP-400C's Binding post terminals
Cabinet Type and Port Position
Both RP-504C II and RP-400C have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Klipsch RP-504C II's and Klipsch RP-400C's external dimensions. Klipsch RP-504C II has external dimensions of 177.0 x 818.0 x 385.0mm (6-15/16 x 32-3/16 x 15-1/8inch) whereas Klipsch RP-400C has external dimensions of 147.0 x 408.0 x 242.0mm (5-3/4 x 16-1/16 x 9-1/2inch).
Klipsch RP-504C II is clearly the larger of the two speakers. Its body is 410mm wider, 30mm taller and 143mm deeper than Klipsch RP-400C.
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the Klipsch RP-504C II is approximately 3149.3cm2 / 488.1inch2 and base area of the Klipsch RP-400C is approximately 987.4cm2 / 153.0inch2. The RP-504C II requires 219% more surface area than the RP-400C which gives it a small disadvantage on placement in tight spaces.
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Klipsch RP-504C II weighs 16.50kg / 36.3lbs and the Klipsch RP-400C weighs 6.36kg / 14lbs. This makes the RP-504C II 159% heavier than the RP-400C.
Here is a comparison of how RP-504C II and RP-400C's weights compare with the average, max and min weights in Passive Center Channel class.
Weight
All Center Channel Speakers
What's in the Box of Klipsch RP-504C II?
Here are the items that are included inside the box of RP-504C II:
- Center channel loudspeaker
- Grille
- User Manual
- Important Safety Instructions
- Warranty Information
What's in the Box of Klipsch RP-400C?
Here are the items that come with the RP-400C:
- Center channel loudspeaker
- Grille (installed)
- 4 Self-adhesive rubber feet
- Tilt rod (attached nut)
- User Manual
- Important Safety Instructions
- Warranty Information
 Max Input Power |
150 watts
vs
75 watts
|
Handle more power from your amplifier |
 Sensitivity |
96 dB
vs
95 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
5.25 inches
vs
4 inches
|
Larger woofer |
|
Number of Woofers |
4
vs
2
|
More woofers |
|
Low Frequency Response |
50 Hz
vs
65 Hz
|
Generates deeper bass |
 Height |
147mm
vs
177mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
987cm2
vs
3149cm2
|
Takes less floor space |
 Price per pair* |
344USD
vs
799USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Klipsch Reference Premiere RP-504C II |
Klipsch Reference Premiere RP-400C |
| Brand |
Klipsch |
Klipsch |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
up to 150 watts |
up to 75 watts |
| Sensitivity |
96 dB |
95 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
50-25k Hz |
65-25k Hz |
Drivers |
|
|
| Woofer Quantity |
4 |
2 |
| Woofer Size |
5.25" |
4" |
| Woofer Composition |
Cerametallic cone |
Cerametallic cone |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Tractrix Horn |
Tractrix horn |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
1950 Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
177.0mm (7") |
147.0mm (5.8") |
| Width |
818.0mm (32.2") |
408.0mm (16.1") |
| Depth |
385.0mm (15.2") |
242.0mm (9.5") |
| Weight |
16.50kg (36.3lbs) |
6.36kg (14lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood-grain vinyl |
MDF/Wood-grain vinyl |
| Available Colors |
Walnut, Black |
Walnut, Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
n/a |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - Klipsch RP-504C II costs roughly 2.3x what Klipsch RP-400C does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass |
A |
Klipsch RP-504C II digs deeper - 50Hz against 65Hz. |
| Amplifier needs |
evenly matched |
Similar sensitivity (96dB vs 95dB) - both want much the same power. |
| Headroom |
A |
Klipsch RP-504C II takes more power (150W vs 75W) - more in hand in a big room. |
| Size |
depends |
Klipsch RP-400C is easier to place; Klipsch RP-504C II is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability |
depends |
Neither adds bi-amping, a sub output or height drivers. Klipsch RP-400C sits in a wider range (17 models), so a matched surround system is easier later. |
| Price |
B |
Klipsch RP-400C is cheaper - $344 against $799, about 57% less; arguably a different class. |
A Klipsch RP-504C II
B Klipsch RP-400C
depends neither is better in the abstract - it turns on your room, placement or how you will use them.
Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: Klipsch RP-504C II measures better, Klipsch RP-400C costs about 57% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 65Hz anyway, which makes the cheaper Klipsch RP-400C much easier to justify. Match it to your room: we rate Klipsch RP-504C II the better fit for a mid-size room and a large room, and Klipsch RP-400C for near-field listening and a small room.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.